Fig. 1.

Il-6 cytokine family–mediated Stat3 signaling is proregenerative.

(A) Illustration of scarring in an adult mammalian heart in contrast to regeneration in an adult zebrafish heart. (B) Quantification of epicardial- and endothelial-derived αSMA⁺ cells after MI in mouse [fibroblasts (3); endothelial cells (4)] and 7 dpci in zebrafish [fibroblasts, Tg(tcf21:CreER), n = 4; endothelial cells, Tg(kdrl:Cre), n = 4]. (C) Schematics of the comparative transcriptional profiling. (D) Results from upstream regulator prediction analysis using Ingenuity Pathway Analysis. (E to H) Bright-field images of larval fin fold regeneration (E and G) [amputated at 48 to 60 hours post fertilization (hpf)] and their corresponding quantification of the fin fold area [(F) (il6st^sa1462, wt siblings, n = 11; mut, n = 9, 48 hpa; (H) stat3^stl27, wt siblings, n = 6; mut, n = 6, 72 hpa]. Data represent means ± SD (B, F, and H). Student’s t tests (F and H). n = larvae (F and H). Black dashed lines demarcate the amputation plane (E and G). Scale bars, 100 μm (E and G).